Make shure you are running 1.4 https://github.com/Nevacoin/nevacoin/releases/tag/v1.4.0

Try shuting down wallet and removing everything except wallet.dat from the nevacoin %appdata% folder.

You can also download nevacoin.conf file here https://github.com/Nevacoin/nevacoin/releases/download/v1.4.0/nevacoin.conf and place it on the nevacoin appdata folder as i have just added current node ips to the file.

The currenc node list can be found by clicking  on "node list" button here https://chainz.cryptoid.info/neva/#!network.

Cheers.